Fingerprint and DNA Evidence in Criminal CasesFingerprint evidence still is used frequently when it comes to criminal investigations and criminal cases. There currently are several high-tech, crime solving methods used during an investigation, but fingerprint evidence still is relied upon often when seeking an offender. Why? No two individuals have the same fingerprints, thus fingerprint evidence is considered to be very reliable, as is DNA evidence. Fingerprints, in particular, contain a unique set of ridges and whorls that is unique to each person.

Identifying Fingerprints
A person’s fingerprints do not change over their lifetime. Each person has a unique pattern of swirled skin on each fingertip, known as “friction ridge patterns.” No one has has the same “friction ridge pattern” as another person. Law enforcement officials collect fingerprints at a crime scene and attempt to match them up with prints already part of police files. Fingerprints may be on file if a person has been fingerprinted for an occupation or if an individual has been arrested in the past.

Finding Fingerprints
Fingerprints often are left behind on surfaces because the ridges on a person’s fingertips contain sweat pores. When sweat mixes with other body oils and dirt, fingerprints result.

Fingerprint experts use powders and chemicals to make prints visible at a crime scene. The visibility of a set of prints depends on the surface from which they’re lifted. Technology now can create a complete pattern from fragments of a print.

Collecting DNA Evidence
Technology has changed many aspects of the investigation process, and the use of DNA evidence represents one of the best examples of how technology has altered the criminal justice system. DNA, or deoxyribonucleic acid, is the basic building block of life. DNA exists in the cells of all living beings. Investigators can collect DNA evidence from a number of different sources, such as from blood or sweat. Forensic investigators will analyze the biological samples to get a DNA profile of the individual that the samples came from. If investigators already have a suspect in mind, they can collect samples to compare to the evidence collected at the scene. There are also databases of DNA profiles that investigators can use to identify suspects. DNA evidence is a highly effective way to match a suspect to biological samples collected during a criminal investigation. Because of its accuracy, lawyers often rely on DNA evidence to prove a defendant’s guilt or innocence.